Migrating MySQL Database to Managed Cloud SQL

C.

When migrating a MySQL database to the managed Cloud SQL database on Google Cloud, it is essential to ensure secure and efficient connectivity between the Cloud SQL instance and the Compute Engine virtual machines. One of the primary challenges is to allow Compute Engine instances to connect to the Cloud SQL instance without explicitly whitelisting their IP addresses. This is because Compute Engine instances may have dynamically assigned IP addresses, and whitelisting IPs can become a cumbersome and error-prone task.

Here are the explanations for each of the options:

A. Enable private IP for the Cloud SQL instance: This option involves configuring a private IP address for the Cloud SQL instance, which can only be accessed by the Compute Engine instances within the same virtual private cloud (VPC). By using private IP addresses, you can avoid whitelisting IPs for Compute Engine instances, as they can communicate with the Cloud SQL instance securely within the VPC. This option is an excellent choice if you want to have a secure and efficient connection between Compute Engine instances and Cloud SQL instances.

B. Whitelist a project to access Cloud SQL and add Compute Engine instances in the whitelisted project: This option involves whitelisting the entire project that contains the Compute Engine instances, and then adding the project to the authorized networks of the Cloud SQL instance. However, this approach can be a security risk as it exposes the Cloud SQL instance to all Compute Engine instances in the project. Additionally, this option may require additional effort to manage project-level access control, as the Compute Engine instances may have different requirements for accessing the Cloud SQL instance.

C. Create a role in Cloud SQL that allows access to the database from external instances and assign the Compute Engine instances to that role: This option involves creating a custom role in Cloud SQL that allows external access to the Cloud SQL instance, and then assigning the role to the Compute Engine instances. However, this option is not recommended for security reasons, as it exposes the Cloud SQL instance to the public internet, which can make it vulnerable to attacks. Additionally, it may require additional effort to manage role-based access control, as the Compute Engine instances may have different requirements for accessing the Cloud SQL instance.

D. Create a CloudSQL instance on one project, create Compute engine instances in a different project and create a VPN between these two projects to allow internal access to CloudSQL: This option involves creating a Cloud VPN tunnel between the project containing the Cloud SQL instance and the project containing the Compute Engine instances. By using a VPN tunnel, you can allow the Compute Engine instances to access the Cloud SQL instance securely over a private network, without the need to whitelist their IP addresses. This option can be an excellent choice if you want to have a secure and efficient connection between Compute Engine instances and Cloud SQL instances, especially if the Compute Engine instances are in a different project than the Cloud SQL instance.

In conclusion, option A, which involves enabling private IP for the Cloud SQL instance, is the most suitable choice for migrating a MySQL database to the managed Cloud SQL database for Google Cloud, while ensuring secure and efficient connectivity between Compute Engine instances and Cloud SQL instances.